Explosive composition containing tnt,hmx,and rdx

ABSTRACT

A fusible explosive composition comprises 40-90% by weight of a crystalline explosive with a high detonation velocity and 60-10% by weight of 2,4,6-trinitrotoluene, the crystalline explosive with a high detonation velocity consisting of 10-50% by weight of octogen, that is cyclotetramethylene-tetranitroamine and the remainder being hexogen, that is cyclotrimethylene-trinitroamine. The use of octogen causes a decrease in the melt viscosity and a decrease of deterioration, that is the increase in viscosity during successive fusions.

[451 Jan. 15, 1974 EXPLGSIVE COMPOSlTION CONTAINING TNT, HMX, AND RDX [75] Inventors: Jean Vaganay, Avignon; Robert A.

Ousset, Sorgues, both of France [73] Assignee: Societe Nationale Des Poudres et Explosifs, Paris, France [22] Filed: Feb. 12, 1973 [21] App]. No.: 331,496

[30] Foreign Application Priority Data Feb. 21, 1972 France 7205 7 26 [52] US. Cl 149/92, 149/18, 149/105, 149/111, 264/3 R [51] Int. Cl C06!) 15/02 [58] Field of Search 149/92, 105, 111, 149/18; 264/3 R [56] References Cited UNITED STATES PATENTS Riedl et a1. 149/105 X 9/1970 Weinland 149/105 X 6/1970 Hamrick 149/105 X Primary Examiner-Stephen .1. Lechert, Jr. Attorney-Bucknam & Archer [5 7 ABSTRACT A fusible explosive composition comprises 4090% by weight of a crystalline explosive with a high detonation velocity and 60-10% by weight of 2,4,6- trinitrotoluene, the crystalline explosive with a high detonation velocity consisting of 10-50% by weight of octogen, that is cyclotetramethylene-tetranitroamine and the remainder being hexogen, that is cyclotrimethylene-trinitroamine. The use of octogen causes a decrease in the melt viscosity and a decrease of deterioration, that is the increase in viscosity during successive fusions.

10 Claims, No Drawings EXPLOSIVE COMPOSITION CONTAINING TNT, HMX, AND RDX shell s, bonibs, mines and thfike. names arenas usually manufactured by mixing hexogen and fused T N T and casting the mixture into the desired shape at a temperature above the melting point of T N T.

This procedure requires that two opposing conditions be satisfied. On the one hand, casting requires that the viscosity of the mixture should be quite low. On the other hand, the concentration of hexogen, which is the more powerful explosive of the mixture, but the majority of which remains in the crystalline form in the fused T N T, should be as high as possible.

In order to increase theh exo gen content of tBE'h'e'xb' lite, the crystalline hexogen is generally allowed to sediment in the liquid T N T and the bottom part of the hexolite thus produced is used, this part having the highest hexogen content.

One of the processes used hitherto to increase the proportion of hexogen in the hexolite consists of using simultaneously several different particle sizes of hexogen, that is large, medium and fine particles, so that the fine grains fill the interstices which exist between the grains of larger particle size. The following improvements are thus obtained: (i) an increase in the performance of the ammunition due to the increase in the proportion of hexogen, whilst it remains easy to cast the mixture and the final charge still remains homogeneous, (ii) there is less need to use special processes, such as sedimentation whic li increa s e the density of the more powerful explosive in the lower layers, the

upper layers being removed and optionally reused in a subsequent preparation, and (iii) a reduction in the cost of the explosive charges since the upper portion, that is to say the part removed and optionally reused in a subsequent preparation, is reduced in size and also can be reused more easily since the proportion of hexogen which it contains is higher.

Thus, hexogens produced by mixing a grade containing more than 60% by weight of particles of size greater than 500 microns, withh a grade containing at least 80% of particles of size less than 300 microns, have been used.

Hexogen mixtures of large particles of 315-800 microns and of fine particles of maximum size less than 200 microns, have also been proposed. A 60/40 mixture by weight of these two hexogens in a 70/30 hexolite (70% by weight of hexogen and 30% by weight of T N T enables a product to be obtained which has a viscosity of 9 seconds, measured on an EFFLUX viscometer at 85 C, and a density of 1.75, in the lower half of the charge obtained after casting in vacuo and sedimentation.

Mixtures of hexogen fractions having particle sizes of 630/1 ,000 microns, 100/200 microns and /100 microns, respectively, have also frequently been used.

The viscosity of a 60/20/20 mixture of such fractions with T N T in the ratio /25 (75% of hexogen and 25% of T N T, measured on an EFFLUX viscometer at C, is l6 to 24 seconds.

As we have indicated above, in order to obtain the maximum proportion of hexogen in the charge, the manufacture of such mixtures necessitates carrying out a sedimentation of the fused mixture after casting. Only the lower part is used for producing the explosive charge, the other part or upper portion being recovered and fused again as a mixture with a fresh amount of hexolite.

Unfortunately, it is found that the viscosity of the hexolite increases after repeated fusions. This phenomenon, which will be called deterioration, is a function of the number of fusions undergone. It becomes apparent more or less rapidly depending on the temperature-at which the fusion is carried out and on the period for which it is kept in the fused state.

It should be noted in passing that the hexolites provided to users as the starting material for manufacturing explosive charges have already been fused in order to coat the hexogen with T N T, which is a good illustration of the importance of the stability of the viscosity during fusion.

We have now surprisingly found that the partial replacement of the hexogen in these mixtures by octogen (that is, cyclotetramethylene-tetranitroamine) greatly decreases or even eliminates the phenomenon of deterioration defined above, manifested by an increase in viscosity during successive fusions.

According to the present invention, therefore, we provide a fusible explosive composition which comprises fro 40 to by weight of crystalline explosive was amgfirretbsarrda veraaiyafiarransma 10%by weight of T N T, from 10 to 50% by weight of the crystalline explosive with a high detonation velocity being octogen and the remainder thereof being hexogen.

The particle size of the octogen is preferably the same as that of the fine fraction of the hexogen, that is preferably between 0 and 300 microns, and the octogen preferably replaces all or part of the fine fraction of the hexogen. The preferred proportion of octogen is from 15 to 25% by weight of the hexogen and octogen taken together.

The hexogen and the octogen incorporated into the fused T N T may have been pre-coated with T N T in order to reduce its sensitivity.

In a modification of the composition according to the invention, a co-crystallised mixture of hexogen and octogen in a weight ratio of from 60/40 to 85/ l 5, preferably 75/2 5fis used in place of the octogen. Such crystals, which we shall call hexo-octo, are produced, in particular, during the manufacture of octogen from hexamethylene-tetraamine and nitric acid.

In order that the invention may be more fully understood, the following examples and comparative experiments are given by way of illustration only:

EXAMPLES A number of hexolite-type compositions were made up, all but two on the basis of 75% by weight hexogen and 25% by weight T N T and in some of these a part of the hexogen was replaced by octogen. Details of the compositions and the viscosities measured when the compositions were repeatedly fused, are given in Table 1 below. It should be noted that the compositions of Experiments 2, 4, 6, 8 and 9 show compositions in and 7 are comparative experiments.

The fusion experiments were carried out by always re-fusing the whole of the hexolite, which made it possible to obtain perfectly comparable results. In industry, however, only the upper portion would be fused several times.

By comparing Experiments 1-2, 3-4, 5-6 and 7-8, respectively, it will be seen that in every case, the addition of octogen greatly reduced the increase in viscosity during re-fusions. Experiment 9 shows the use of octogen having a particle size of 100-200 microns.

An example carried out with a mixture containing 23% of T N T has shown that the viscosity remains very acceptable even with such a low proportion ofT N T. The proportion of T N T in the mixture can, of course, be reduced subject to accepting higher viscosities, which then require the use of particular methods of sedimentation, such as centrifuging or the application of vibrations, which makes it possible to reduce the proportion of T N T to about 10%.

in the case of Experiments 3, 4, 5 and 6, the following table shows losses in fluidity as a percentage relative to the fluidity during the first fusion.

EXFERTRTENT um i 3 7' 4 5 6 Loss in fluidity during the first fusion -2l% 18% -347 l6% Loss in fluidity during the second fusion 79% 43% 300% -32% minimum Experiments 4 and 6, which were carried out with. mixtures according to the invention, show very clearly that the results are markedly improved.

This improvement has also been verified in the case of 75/25 hexolites in which the fine fraction of hexogen is replace d by aid-crystallized hexogen/octogen material, i.e. a hexo-octo material. The results of two experiments carried out with this product are given below.

Particle size of the explosive EFFLUX Viscosity 2nd 3rd 630/800 100/200 0/100 fusion fusion fusion hexogen hexogen hexo-octo 85C 90C 90C 60 20 20 15.8 13.4 13.4

Crystalline explosive Viscosity 1st 2nd 3rd Hcxogen Hexogen fusion fusion fusion 800/1000 0/200 85C 90C 90C 60 22.5 24.0 30.2 octogen 0/200 We have observed that the temperature at which the first fusion is carried out plays an important role on the way in which the viscosity changes during successive fusions.

The following values, mentioned by way of example, illustrate this result.

x The octogen used had a particle size of 100-200 microns.

(x) The octogen used has a particle size of 100-200 microns.

it is thus seen that the fact that the first fusion was carried out at about C markedly reduces the viscosities during the second and third fusions.

By comparing Experiments 1 and 3 on the one hand, and 2 and 4 on the other hand, of Table I, it will also be seen that aging is apparent from the first fusion carried out to charge a piece of ammunition and that this phenomenon is reduced by introducing a fine fraction of octogen in place of the hexogen of the same particle size.

What is involved in this case is a manifestation of the same phenomenon of aging. In effect, what we are calling here the first fusion is, in fact, the second since the first is, as stated above, that which is carried out to form a coating of T N T around the hexogen or the octogen.

It is apparent from all that has been stated above that the replacement of a part of the hexogen in hexolites by octogen, particularly octogen of fine particle size, leads to the following improvements: (i) decrease in the melt viscosity, (ii) decrease in the phenomenon of deterioration during successive fusions, which manifests itself, in general, by an increase in viscosity which can be so great as to prevent casting completely, (iii) improvement in the sedimentation of the crystalline explosive in the fused T N T which increases the density of the more powerful explosive in the lower layers .of the explosive mixture, (iv) economy due to the reduction in the amount of the upper portion which has to be removed, (v) improvement, of the order of metres per second, in the detonation velocity in the case of 40% octogen replacement, which compensates for the higher price of octogen relative to that of .hexogen, and (vi) the possibility of using a cheap byproduct, that is hexo-octo.

Particle size distribution of hexogen octogen combination TABLE I Proportion of octogen in the hexogen plus Viscosity (EFFLUX) No. of experiment 630800;t loll-200 0400;; (k100 1110-200 1st fusion 2d fusion 3d fusion Experiments carried out with 73-27 hexolites.

which from to 25% by weight of the crystalline explosive with a high detonation velocity is cyclotetramethylene-tetranitroamine and the remainder being cyclotrimethylene-trinitroamine.

3. An explosive composition according to claim 1, in which the particle size of the cyclotetramethylenetetrargroamine is between 0 and 300 microns.

4. The composition according to claim 1, which comprises a co-crystallized mixture of cyclotrimethylene-trinitroamine and cyclotetramethylenetetranitroamine in a weight ratio of from 60/40 to 85/ l 5.

5. An explosive composition according to claim 4, in which s aid'co-crystallized mixture isa by-product of the manufacture of cyclotetramethylenetetranitroamine from hexamethylenetetraamine.

6. A process for molding an explosive composition, which comprises fusing at about 85 C a composition explosive with a high detonation velocity and from 60 to 10% by weight of 2,4,6-trinitrotoluene, from 10% to 50% by weight of said crystalline explosive being cyclotetramethylene-tetranitroamine and the remainder being cyclotrimethylene-trinitroamine, casting said fused composition in to t he desired shape, rem ov i n ga portion of the cast material, repeating said steps of fusion and casting, each subsequent fusion being carried out at about 90 C.

7. The process according to claim 6 wherein said portion of the cast material which is removed is the upper portion.

8. The process according to claim 6 wherein said cyclotetramethylene-tetranitroaminc and said cyclotrim; ethylene-trinitroamine of said explosive composition are precoated with fused 2,4,6-trinitrotoluene prior to fusion at 85 C.

9. The composition according to claim 1 which comprises 27% of 2,4,6-trinitrotoluene and 73% of said crystalline explosive wherein 10% by weight thereof is cyclotetramethylene-tetranitroamine.

10. The composition according to claim 1 which comprises 25% of 2,4,6-trinitrotoluene and 75% of said crystalline explosive wherein 15-20% by weight is cyclotetramethylene-tetranitroamine. 

2. An explosive composition according to claim 1, in which from 15 to 25% by weight of the crystalline explosive with a high detonation velocity is cyclotetramethylene-tetranitroamine and the remainder being cyclotrimethylene-trinitroamine.
 3. An explosive composition according to claim 1, in which the particle size of the cyclotetramethylene-tetranitroamine is between 0 and 300 microns.
 4. The composition according to claim 1, which comprises a co-crystallized mixture of cyclotrimethylene-trinitroamine and cyclotetramethylene-tetranitroamine in a weight ratio of from 60/40 to 85/15.
 5. An explosive composition according to claim 4, in which said co-crystallized mixture is a by-product of the manufacture of cyclotetramethylene-tetranitroamine from hexamethylenetetraamine.
 6. A process for molding an explosive composition, which comprises fusing at about 85* C a composition comprising from 40 to 90% of weight of a crystalline explosive with a high detonation velocity and from 60 to 10% by weight of 2,4,6-trinitrotoluene, from 10% to 50% by weight of said crystalline explosive being cyclotetramethylene-tetranitroamine and the remainder being cyclotrimethylene-trinitroamine, casting said fused composition into the desired shape, removing a portion of the cast material, repeating said steps of fusion and casting, each subsequent fusion being carried out at about 90* C.
 7. The process according to claim 6 wherein said portion of the cast material which is removed is the upper portion.
 8. The process according to claim 6 wherein said cyclotetramethylene-tetranitroamine and said cyclotrimethylene-trinitroamine of said explosive composition are precoated with fused 2,4,6-trinitrotoluene prior to fusion at 85* C.
 9. The composition according to claim 1 which comprises 27% of 2,4,6-trinitrotoluene and 73% of said crystalline explosive wherein 10% by weight thereof is cyclotetramethylene-tetranitroamine.
 10. The composition according to claim 1 which comprises 25% of 2,4,6-trinitrotoluene and 75% of said crystalline explosive wherein 15-20% by weight is cyclotetramethylene-tetranitroamine. 